Flipper arm assembly for sensing switches with backing off movement



Aug. 12, 1969 D. D. CALL 3,461,255

FLIPPER ARM ASSEMBLY FOR SENSING SWITCHES WITH BACKING OFF MOVEMENT Filed Aug. 7. 1967 United States Patent 3,461,255 FLIPPER ARM ASSEMBLY FOR SENSING SWITCHES WITH BACKING OFF MOVEMENT Daniel I). Call, Mount Prospect, 11]., assignor to Bell and Howell Company, Chicago, 111., a corporation of Illinois Filed Aug. 7, 1967, Ser. No. 658,721 Int. Cl. HOlh 3/16 U.S. Cl. ZOO-61.42 12 Claims ABSTRACT OF THE DISCLOSURE A switch for sensing travelling sheets has flipper arms which are yieldably mounted on a rotary operator to avoid thrusting into a preceding sheet when an overlappingly related succeeding sheet drives an arm which is still in engagement with the preceding sheet.

This invention is concerned with improvements in sensing switches of the paddle wheel or flipper arm type, and more particularly relates to improvements in switches of the type exemplified and covered in my Patent No. 3,202,779, dated Aug. 24, 1965 and assigned to the same assignee as the present application.

Switches of the type covered by the aforesaid patent have been extensively utilized for individually sensing serially moving members, and more especially sheet-form members such as checks, cards, record sheets of various sorts for various purposes, including actuating a functioning unit such as a check endorser, counting mechanism, and the like.

In the aforesaid patent, the flipper arms are mounted fixedly on the rotary operating member. Occasionally a succeeding sheet will overlap a portion of the preceding sheet, whereupon the flipper arm driven by the succeeding sheet thrusts into the preceding sheet and tends to retard the same and sometimes causes a jamming thereof in the flow path. It is to the solving of this problem that the present invention is directed.

Accordingly, it is an important object of the present invention to provide a flipper arm assembly for sensing switches which will avoid thrusting of a flipper arm into a preceding sheet when an overlappingly related succeeding sheet drives the arm which is still in engagement with the preceding sheet.

Another object of the invention is to provide a switch of the character indicated, and having at least one flipper arm, in which the flipper arm is yieldably biased to avoid interfering with free movement of a sheet against which the arm engages in the normal operation of the switch in ready position of the arm for driving by the next succeeding sheet.

A further object of the invention is to provide a new and improved yieldable mounting of the flipper arms of rotary sensing switches which will increase the speed of operation, will reduce the resistance to movement of sheets past the switch, and will avoid any danger of jamming where a succeeding overlapping sheet drives the arm for operating the switch before the preceding sheet has cleared the switch.

Another object of the invention is to provide a new and improved paddle wheel sensing switch construction in which the flipper arms are mounted in a novel yieldably biased manner.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is an elevational view of a sensing switch ice embodying features of the present invention, and showmg the same operatively associated with means for serially moving sheet members to be individually sensed along a guided path under normal operating conditions;

FIGURE 2 is a similar view demonstrating operation of the switch when a succeeding sheet is fed along the lath in partially overlapping relation to the preceding s eet;

FIGURE 3 is a sectional detail view taken substantially along the line III-III of FIGURE 1;

FIGURE 4 is a side elevational view taken substantially along line IV--IV of FIGURE 3;

FIGURE 5 is a side elevational view of a modified flipper arm construction for the switch; and

FIGURE 6 is a sectional detail view taken substantially along the line VIVI 0f FIGURE 5.

By way of example, a sensing switch 10 according to the principles of the present invention comprises a housing body 11 which is desirably molded from a suitable dielectric material such as a synehtic plastic and provided with a switch chamber cavity 12 which opens from one side of the body and is closed by a cover panel 13 which may be made from a transparent plastic material to enable inspection of the interior of the chamber. Within the chamber 12 is mounted a pair of opposed spaced leaf spring switch arms 14 and 15 attached in cantilever fashion to respective stepped lands or platforms 17 and 18, respectively, integral with the housing, and carrying on their free end portions respective contacts 19 and 20 in normally separated open switch relation as shown in FIGURE 4. Electrical connection of the switch arms 14 and 15 in an electrical circuit to be controlled by the switch is effected by suitable electrical connection of the switch arms with respective electrical leads 21 and 22 attached to the switch externally of the chamber 12.

Rotary operating means for intermittently closing the switch contacts 19 and 20 comprise a combination switch operating and detenting member 23 desirably made from a suitable dielectric material and corotatably mounted on the inner end portion of a shaft 23 which is journalled through the wall of the housing 11 opposite the closure 13 and an outwardly projecting bearing hub 25 (FIG. 3). On its outer end portion, the shaft 24 has corotatably aflixed thereto a paddle wheel or flipper finger or arm assembly comprising a hub 27 and flipper arm means comprising at least one, and in the present instance three equidistantly spaced arms 28 arranged generally paddle wheel fashion about and projecting from the hub.

In use, the switch 10 is mounted in suitable manner for projection of the arms 28 successively in. the rotation of the hub 27 into the path of movement of successive sheetform members 29 which may be propelled by feed rollers 30, for example, into and through a guideway provided by suitably spaced parallel plates 31 provided with aligned clearance slots 32 therethrough to accommodate the flipper arms 28 to extend operatively into and across the path of movement of the advancing sheet 29. Disposition of the arms 28 on the hub 27 is such that the triggerpoised arm at any instant in the path of movement of the sheets is inclined toward the advancing edge of the sheet member 29, with an oblique contact surface 33 assuring eflicient engagement of and driving of the arm in the advancing direction of the sheet by the leading edge thereof, substantially as indicated by comparison of the full line and dash line positions of the topmost arm in FIGURE 1. Then as the engaged arm moves arcuately as driven by the advancing leading edge of the sheet, the contact face offers minimum and substantially frictionless opposition to the sheet edge.

In the arrangement disclosed, as each of the arms 28 is driven by the successive sheets 29 closing of the contacts 19 and 20 occurs by action of the cam detent 23. For this purpose, this member has respective cam projections 34 corresponding in number to the flipper arms 28 and so located with respect to the respective arms as to depress the spring arm toward the spring arm 14 as the corresponding flipper arm is swung and in high speed operation flipped by an advancing sheet member, thereby closing the contact against the contact 19. Further the arrangement is such that movement of each of the cam projections 34 by driving of the associated arm 28 is sufliciently beyond center in each instance to cause the biasing rebound of the spring arm 15 to snap the cam member and thereby the arms 28 into the next ready or dwell position wherein the next succeeding projection 34 serves as a detent in engagement with the spring arm 15 to stop rotation of the rotary assembly until the next succeeding flipper arm 28 is driven by an advancing sheet. At the same time the contact 20 breaks away from the contact 19 by reason of the resilient spring back of the switch arm 15. At the same time, by its resilient cantilever thrust against the spaced cam projections 34, the spring arm 15 serves as a detent preventing overrun of the flipper arm rotor, and, in the absence of a next succeeding sheet or in a space interval between sheets holds the rotor in position with one of the flipper arms 28 in intercepting relation to the leading edge of the next succeeding sheet.

Means are provided to aflord safe, minimal resistance contact and freedom from jamming in respect to the cyclically sequential flipper arm 28 moved toward operating, sheet intercepting relation, and which engages the trailing portion of the sheet which has just motivated the switch, and especially in those instances when a succeeding sheet is fed in lapping relation to the preceding sheet. To this end, each of the flipper arms 28 is mounted for backing off movement relative to the flipper wheel hub 27, namely, in the trailing direction relative to the direction of operating rotation of the wheel and from an operating position toward which the arm is normally yieldably biased. In one manner of accomplishing this, the arms 28 are pivotally mounted on the wheel hub by means of pivot pins 35 mounted in and between the walls defining an annular radially outwardly opening groove 37 in the outer perimeter of the flipper wheel. Each of the arms 28 has a heel 38 extending generally inwardly from the pivot and engaging an abutment perimeter surface 39 on the hub 27 and defining the root surface of the groove 37. Normally the heel 38 is biased into separable abutment with the surface 39 by means comprising a tensionably loaded sear spring 40 coiled about the pivot pin 35 of the associated flipper arm 28 within a bifurcation slot 41 in the inner end portion of the arm and with one terminal of the spring thrusting against the hub surface 39 and the other terminal thrusting against the associated arm, substantially as shown. Thereby, the flipper arm normally projects into operating position. However, such bias by the spring 40 is reasonably light so that the flipper arm 28 may fairly easily yield resiliently upon engagement with the face of the trailing portion of the sheet which has motivated the flipper wheel of the switch to bring the next succeeding flipper arm toward operating position, substantially as shown in FIGURE 2. This affords desirable pressure relief in respect to the face-contacting flipper arm against such sheet and permits the cam 23 instantaneously to assume the full detent position during the incremental advance of the switch rotor by the sheet, and full opening of the switch contacts. When the sheet against which one of the flipper arms 28 engages, as shown in FIGURE 2, passes beyond such arm, the spring 40 snaps the arm into its normal operating position as shown in dash outline so as to intercept the next succeeding sheet following in gap or spaced relation.

However, when the succeeding sheet is fed in lapped relation, as shown in FIGURE 2, its leading edge will engage the tip portion of the confronting arm 28, substantially in the manner indicated. Since the arm 28 is relatively freely movable relative to the flipper wheel hub 27, in the trailing direction, the arm is driven by the advancing sheet but without thrusting objectionably into the surface of the opposed face of the trailing portion of the preceding sheet. Therefore, advance of the succeeding sheet may take place without interruption, and without danger of jamming of the preceding sheet by the operational flipper arm which thus functions efficiently to advance the switch rotor in an increment of switch operation.

Although in FIGURES 1 and 2 the switch 10 is depicted as mounted on one side, in this instance the underside, of the sheet path to sense the passage of successive sheets fed from the top of a stack of such sheets, a reverse arrangement may be employed where the sheets are fed from the bottom of a stack or at least in such a manner that a succeeding sheet may tend to overlap rather than underlap the trailing portion of the preceding sheet. Such a reversal of the arrangement is depicted in FIGURE 5 in which the structure differs from FIGURES 1 and 2 only in that a modified flipper or paddle wheel for the switch has been provided. In this arrangement, there is corotatably mounted on the outer end portion of the shaft 24 an equilateral triangular combination switch operating and detenting dielectric hub member 41 (FIGS. 5 and 6). On each of the triangularly related faces of the hub member 41 is mounted a flipper finger arm 42 in generally paddle wheel fashion. Each of the arms 42 is preferably of identical construction, and may be made from a suitable strip of sheet metal.

For resilient yieldability of the respective flipper arms 42 upon engagement with the trailing face portion of a sheet 29 which has advanced the flipper wheel by one operating increment in passing by the sensing switch, each of the fingers 42 is longitudinally slidably carried by its face of the hub 41. For this purpose, each of the hub faces has thereon a headed retaining and guide stud 43 with its shank extending through a longitudinal slot 44 of limited length in the associated arm 42 and so disposed as to control the extent of normal projection of the arm from the hub 41 under the influence of a respective biasing spring 45, in. this instance of the expansile tension type attached at one end to a lateral lug 47 on the tail end portion of the arm and at its opposite end to an anchoring stud 48 projecting from the outer face of the hub. Further longitudinal guidance for the respective arms 42 is afforded by the provision on the tail ends thereof of respective narrow tail extensions 49 which project through respective elongated guide slots 50 in the arms 42 intersected in each instance by the respective tail extension. Through this arrangement, the arms 42 are normally projected into a normal operating position in which the respective arm which is in intersecting relation to the leading edge of the next succeeding sheet 29 has an angled receiving distal terminal 51 in a position to receive the leading edge for driving of the engaged arm by the sheet in flipper wheel advancing, and thereby switch operating relation. Should the advancing sheet not have cleared the receiving position assumed by the next succeeding one of the flipper arms 42, such arm will, of course, engage the surface of the trailing portion of the sheet. Such engagement is substantially eased against frictional resistance to movement of the sheet past the thrusting arm terminal by resilient yielding of the associated biasing spring 45 and backing off rectilinear movement of the arm until the trailing end of the sheet has passed the arm whereupon the spring snaps the arm into intercepting relation to the next succeeding sheet leading edge. Should such next succeeding sheet leading edge be in overlapping relation to the preceding sheet so that the thrusting arm is advanced in a switch operating rotary increment, the arm is enabled to continue backing off as it advances with the overlapped driving sheet until the incremental switch operating advance has been completed.

It will be understood that the arms 42 may be biased into their operative position by a combination of centrifugal force and gravity or either, although the action tends to be slower and less positive and not entirely suited to a high speed operation. This mode of action can easily be understood from FIGURE 5 by the removal of springs 45. The same result can be accomplished with the embodiment of FIGURE 1 when disposing it above the guideway, as in the case previously described wherein sheets are fed from the bottom of a stack.

It will be understood that variations and modifications may be effected without departing from the spirit and scope of the novel concepts of this invention.

I claim as my invention:

1. In a switch of the character described having rotary operating means and at least one sensing arm arranged to be swung from an intercepting position by an advancing member to effect rotation of said operating means:

means mounting said arm on said operating means for backing off movement relative thereto from a normal operating position;

said arm being normally biased toward said normal operating position;

whereby if a trailing portion of an advancing member has not cleared the intercepting position when said arm reaches it in the rotation of said operating means, so that said arm thrusts generally endwise against a surface of the member, the arm will back off.

2. A switch as defined in claim 1, in which said am is pivotally mounted on said operating means.

3. A switch as defined in claim 2, in which said operating means has an abutment and said arm has a heel which engages the abutment in said normal operating position.

4. A switch as defined in claim 1, in which said operating means includes a shaft having a hub thereon, said hub having a generally radially outwardly opening recess therein, and said arm is mounted in said recess to project in a generally radial direction from said hub.

5. A switch as defined in claim 4, in which said recess comprises an annular groove, said arm being pivotally attached to said hub within said groove, biasing means comprising a spring engaging said arm and said hub, said hub having an abutment surface, said arm having a heel engaging said abutment surface in said normal operating relation, and a plurality of additional like arms being mounted in said groove in equidistantly spaced relation to said first mentioned arm for incremental step rotary advance of the operating means in operation.

6. A switch as defined in claim 1, in which said arm is mounted for reciprocal movement along its length.

7. A switch as defined in claim 6, in which said operating means comprise a shaft having a hub thereon and said hub has a flat face, said arm comprising a flat elongated member, and means retaining said arm in face-to-face relation slidably on said face and for guiding the arm in rectilinear movement along said face.

8. A switch as defined in claim 7, in. which said hub has a plurality of similar faces arranged in equal sequential order about the perimeter of the hub, each of said faces having thereon one of said arms, each of said arms having a longitudinal slot therein, and each of said arms having a tail extension projecting through the slot in the adjacent arm as a rectilinear guide.

9. In combination with means for advancing a succession of sheets and including means defining a path of movement for the sheets, an electrical sensing switch comprising a body mounted adjacent to said path, electric signal eflecting means carried by said body, a shaft rotatably supported by said body and having means thereon for operating said electric signal effecting means in the rotation of the shaft, a flipper wheel mounted co-rotatably on the shaft and having projecting therefrom in generally radial direction a plurality of equally spaced flipper arms in generally paddle wheel relation and disposed to extend into intercepting relation to the successive sheets moving along said path, and releasable detent means for successively orienting the rotary position of the shaft to locate the arms successively and respectively in intercepting relation to the sheets, the improvement comprising:

means mounting said arms on said wheel for backing ofi movement relative thereto from a normal operating relationship;

and means yieldably biasing said arms toward said operating relationship whereby if a trailing portion of an advancing sheet which has flipped one of said arms to operate the switch has not cleared the next succeeding arm such succeeding arm may engage the surface of the trailing portion of the sheet and yieldably back off from its normal operating relation to the wheel, and if a succeeding sheet is disposed in lapping relation to said trailing portion and the leading edge of the succeeding sheet engages said next succeeding arm to advance the flipper wheel continuing backing off of such succeeding arm while in. engagement with said trailing portion'will avoid undesirable thrusting thereof into the trailing sheet portion.

10. The structure of claim 9, in which said means yieldably biasing said arms comprise springs having respective terminals engaging the arms and the Wheel.

11. A switch according to claim 1, having biasing means yieldably biasing said arm into said normal operating position.

12. In a switch of the character described having rotary operating means and a plurality of sensing arms projecting therefrom in generally radial direction arranged to be swung from an intercepting position by an advancing member to effect rotary motion of said operating means:

means individually mounting each of said' arms on said operating means for backing off movement relative thereto from a normal operating position independently of said other arms;

said arms being normally biased toward said normal operating position;

whereby if a trailing portion of an advancing member has not cleared the intercepting position when one of said arms reaches it in the direction of said operating means, so that said one arm thrusts generally endwise against a surface of the member, the arm will back off.

References Cited UNITED STATES PATENTS 2,987,591 6/1961 Ortenblad ZOO-61.42 X 3,115,556 12/1963 Hodne 200-46 2,517,984 8/1950 Cunningham 235-61.11 2,974,862 3/1961 Eichorn 235-98 ROBERT K. SCHAEFER, Primary Examiner ROBERT A. VANDERHY E, Assistant Examiner US. Cl. X.R. 200-46; 235-98 

